The lights and lenses only need to be D.O.T. rated which has a certification for use.

You legally can put any light on any vehicle as long as it meets federal D.O.T. standardsfor use on a motor vehicle... Has nothing to do with "original equipment limitations" otherthan cannot be "LESS" than acceptable by your insurance company.

I skimmed through about 1/2 of FMVSS 108 last night and didn't see anything about degrees of visibility for rear lights except something about 45 degrees. There are a lot of references to SAE standards and maybe the 135 degree requirement is there. Reading federal vehicle regulations is almost as bad as reading the tax code!

That being said, I do note that my bus (in stock form) has the rear lights set up in such a way as to be visible from both the side and rear. The LED lights I was planning to use would probably not be visible much to the side. There are so many lights required on a bus that only the blind could miss a bus at night.

I skimmed through about 1/2 of FMVSS 108 last night and didn't see anything about degrees of visibility for rear lights except something about 45 degrees. There are a lot of references to SAE standards and maybe the 135 degree requirement is there. Reading federal vehicle regulations is almost as bad as reading the tax code!

Brian,

You have correctly surmised that the angle of visibility requirements are defined in the SAE standards. The SAE requirements are incorporated directly into the federal code by reference (and the state codes must follow the federal codes through a different set of arcane laws).

Here is what I wrote on the topic on the other board, in an argument about whether it is legal to use drop-in replacement LED "bulbs" in an incandescent fixture (it's not):

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I refer you to Federal Motor Vehicle Safety Standard 108, also known as 49CFR571.108 (and it's Canadian counterpart, CMVSS 108) which says, in part, that required lamps must conform to certain SAE specifications. For Stop lamps, that would be SAE J586c, and for Turn Signals, SAE J588d.

Both of those reference SAE J573d, "Lamp Bulbs and Sealed Units" which requires the filament of the bulb to be within 0.01" of the position specified by the manufacturer when the lamp was designed. Filament positions are specified in section 5.1.1.17

LED "drop-in" replacements do not meet the specified filament positioning, therefore they do not meet SAE J573d, thus making the installed fixture in violation of SAE J586c or J588d, thus violating 49CFR571.108 making it UNLAWFUL.

I don't know how much clearer I can be on this, and you making blanket statements like "Nor is it prohibited" without, apparently, even a cursory attempt to research the law is irresponsible.

We could debate until the cows come home about whether an aftermarket lamp could conceivably be inserted into a fixture and meet the photometric standards (and, if they could, then a manufacturer could, conceivably, certify the resulting combination of specific fixture and specific LED as compliant). But as the law is written today, it simply is not lawful to do so.

Nor is it lawful to, for example, retrofit an HID lamp envelope into a headlight system designed for an incandescent lamp. That does not stop hundreds of companies from selling retrofit kits (most of which have "off road only" weasel language on the package) -- the presence in the marketplace of these items does not make it legal to use them on the highway.

FMVSS 108 and the SAE standards are actually quite particular about what you can put on a highway-legal motor vehicle.

Anyway, the reason I asked for the code cite is that I know full well that it does not exist. That individual also went on to say that "... brightness [is the] the only important quality of a light bulb ..." which is also incorrect; as you can see from my description, the precise location of the filament is also important and explicitly defined in the law, as is the photometric output of the lamp at various angles.

The law does not contemplate individuals photometrically testing their own lamps. Instead, it relies on manufacturers doing this testing and then certifying that their fixtures meet the SAE requirements. Such compliant fixtures have appropriate markings embossed on the lenses to indicate compliance.

As long as you use DOT-approved fixtures (in accordance with their directions -- for example, if it says that it must be mounted within so many degrees of vertical, then that's the way you have to mount it), equip them with the bulbs for which they were designed, and follow the placement requirements that I linked from the NHTSA earlier in this thread, you are covered. There is no requirement that you use the same fixtures (or number of fixtures) that the OEM coach builder used, or that you do individual testing of your coach to photometric standards. (Of course, the fixtures can not be recessed or otherwise mounted such that part of the vehicle obstructs its visibility from all intended directions.)

Note, BTW, that some fixtures are approved for "combination" use. For example, a single "corner" fixture photometrically tested at 45°, if so listed, may be used as both the rear clearance lamp and rear side marker lamp.

Most of us, I think, find the minimum defined by the standards to be not entirely sufficient. For example, there is no requirement for side-mounted turn signals, yet every major coach builder puts them in. I have them front, center, and rear, mounted just underneath the required side markers/reflectors.

1. I noted on my trip home from work a little earlier today that basically every car on the road today has wrap around light fixtures so that light from the rear lights radiates to the sides and rear both.

2. The NHTSA lighting requirements document featured at several of the lighting websites seems to indicate for a bus under sections 4ab and 5ab that side lighting is required at the front and rear. My side marker lights are over the front and rear wheel wells with an additional light centered midway between the other two. The two over the wheel wells are also turn signals.

I have decided to keep the LED lights on order as I can always return them if I don't open them. I have to believe that no cop is ever going to write me up for lighting violations as long as all of the lights work.

1. I noted on my trip home from work a little earlier today that basically every car on the road today has wrap around light fixtures so that light from the rear lights radiates to the sides and rear both.

That's actually a cost-saving measure.

For cars (similar to the bus standard I posted), one is required to have a red tail lamp showing to the rear, AND a red side marker showing to the side.

By using wrap-around lenses, they get away with a single fixture to serve both purposes. This, BTW, is a key reason why you can't simply plop an LED "1157"-type replacement into an incandescent fixture -- while it might provide enough luminous intensity directly to the rear, in this application, it is almost certain that not enough light will be emitted to the side.

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2. The NHTSA lighting requirements document featured at several of the lighting websites seems to indicate for a bus under sections 4ab and 5ab that side lighting is required at the front and rear. My side marker lights are over the front and rear wheel wells with an additional light centered midway between the other two. The two over the wheel wells are also turn signals.

I think if you look again, you will find there is actually also a side marker at the rear-most end of the coach, mounted at the top. This is the one which actually meets the standard (item 5a in the chart), not the one over the wheel well, which is an optional auxiliary side marker. Likewise for the front -- there will be one at the top front side corner, which meets item 4a of the standard, and the one over the wheel well is extra and optional.

2. The NHTSA lighting requirements document featured at several of the lighting websites seems to indicate for a bus under sections 4ab and 5ab that side lighting is required at the front and rear. My side marker lights are over the front and rear wheel wells with an additional light centered midway between the other two. The two over the wheel wells are also turn signals.

I think if you look again, you will find there is actually also a side marker at the rear-most end of the coach, mounted at the top. This is the one which actually meets the standard (item 5a in the chart), not the one over the wheel well, which is an optional auxiliary side marker. Likewise for the front -- there will be one at the top front side corner, which meets item 4a of the standard, and the one over the wheel well is extra and optional.

Okay, I looked at the requirements again. 5a and 5b are already met by the marker lights up top and pair of reflex reflectors on the rear of the bus. 4a is met by the roof line marker lights and on my bus 4b is met by having a reflector built into the front turn signal/parking light. If I went LED for the front turn signal/parking lights I would just need to add a reflector to the side.

It appears that front parking lights are not actually required on a bus since it is more than 2032mm wide (80 inches). It would be silly not to have front parking lights in my mind.

Thanks for your help Sean. I am planning to keep moving forward with my LED lighting project.

the Gambler a surplus RV dealer in Quartzsite each winter has complete new lights the latest style in stock. I know he is a full time surplus dealer and only setup in Q town each winter but you can do a search of dealers of Quartzsite and I'm sure you will find a listing

Larry H

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Savvy ponderable:A cowboy's only afraid of two things:havin' ta walk,and the love of a good woman."This posting was generated using an environmentally friendly, self contained flatulence generator, therefore no fossils or neutrons were harmed in the creation of this posting.

And you can go too bright. Looking at Ace's H3, we see 4 red lenses on each side, plus the one in the middle. The stock wiring has two on each side for brake lights and two for running lights. When you get the LED's that ACE bought, they are wired for both running and brake lights. If you had the dealer instal them, they would keep the same configuration, that is two braker lights and two running lights per side.

When I was first looking into relacing mine, the shop forman at Prevost said he had just replaced all the lights on the back of a customer's H3, and the customer had specifically requested thet all four on each side be BOTH brake and running lights. He said that when the customer left the Mira Loma facility, that the lights really lite up the back wall which was 150 ft away. Later, that same customer received a ticket from the highway patrol for having lights that were too bright!

I had never heard of that, but I must admit those LED's are very bright especially when all of them are wired together. So keep that in mind when installing new ones.

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Jim StewartEl Cajon, Ca. (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep and permanent, in the ideas of living.

I would like to second the comment about being careful not to make them overly bright. One of my personal pet peaves are the folks who have no clue how to properly use rear fog lights. It is an incredible annoyance for people to follow one of these yahoos who leave them on constantly, even in clear weather.